Driving mechanism for valve cutoff indicators



v F. D. WELDEN Feb. 2, 1943. 2,309,684

DRIvI-NG MEcHANIsM FOR VALVE GUTOFF- INDICATORS y 2 Sheets-Shee I lFiled Dec. 5, 1941 L `.J Y

Feb 25 1943l F. D. WELDEN 2,309,684

DRIVING MECHANISM FOR- VALVE CUTOFF INDICATORS Filed Dec. 5, 1941 `2Sheets-Sheet 2 FAY D. WELDEN BYpm-f, la

ATTORNEYS Patented Feb. 2, 1943 peut star ATENT GFFICE DRIVINGli/[ECHANISB/I FOR VALVE CUT-GFF INDICATORS Fay D. Wolden. Tuckahoe, N.Y., assignor to Val-ve Pilot Corporation, New York, N. Y., a corporationof New York 8 Claims.

This invention relates to. means for operating the valve cut-01Tindicator of a steam locomotive valve pilot. In Caracristi Patents Nos.1,627,076 and 1,794,381 instruments are described 4by which all oi thefactors governing cut-off which produce the maximum result at differentspeeds are converted into a single expression in terms of surface speedand combined with speed indicating mechanism. A pair of needles orpointers move over a common instrument dial mounted in the cab, one ofthese needles giving the converted reading based on the various factorsgoverning cut-ofi, the other needle indicating speed. By keeping the twoneedles in registry, the engineer is assured that he is using the propercut-off for maximum output for each speed. The cut-off needle isactuated thro-ugh connections with the reverse mechanism, which is usedto vary the cut-oil. A rod connected to an arm on the tumbling shaftoscillates a cam in response to changes in cut-ofi, and a cam-follower,pressed against the cam by means of springs, is connected to a cablewhich actuates the needle in the cab. The conversion of the cut-offfactors into a single expression is effected by means of the cam whichis designed according to principles disclosed in Caracristi Patent No.1,627,075. The whole apparatus, equipped with both indicating andrecording instruments, is known as a valve pilot.

In practice it has been necessary to mount the cam box close to thetumbling shaft and, consequently, it has been necessary to employ arelatively long cable and cable conduit extending along the boiler fromthe cam box to the instrument within the cab. There are certainobjections to this arrangement: (l) The springs urging the followeragainst the cam must exert a maximum pull of 55 pounds in order toinsure the proper actuation of the cut-01T needle, and this hasnecessitated the use of a large and er'- pensive cam box. (2) Therepeated expansion and contraction of the boiler, alternating betweenperiods of use and rest, introduce errors in the hook-up whichnecessitate frequent adjustments of cam and cable settings. And (3) thecam being separated from the indicating instrument by the length of thecable, errors arising through maladjustment of connections between thetwo, including the one enumerated above, are inevitable.

It is the object of the present invention to overcome these objections,an object that I have attained by moving the cam to the instrumentitself, where it acts directly on the cut-orf indicating mechanism, andoscillating the cam in response to changes in cut-off by means of ahydraulic pressure transmitting system. Only very light springs are thusrequired to hold the follower against the cam, because, With theelimination of the long cable and the friction developed within itscurving conduit, the Work done by the cam is greatly lessened `and theneed for a separate cam 'box is eliminated. Expansion and contraction ofthe boiler do not adversely affect the hydraulic pressure transmittingsystem and introduce errors requiring adjustments, `and as the earn actsdirectly on the instrument it is designed to control, there are nointermediate connections to suffer maladjustmen-t.

In the accompanying drawings I have illustrated a preferred embodimentof my invention. In these drawings, Figure 1 is Va side elevation of aconventional locomotive showing the mechanism of the present inventioninstalled, and Figure 2 is a diagrammatic layout of the mechanism.

In these drawings, l indicates the cut-oir valve. This valve is.reciprocated through the Vusual operating gear comprising a pitman 2driven from the middle driver, a link 3 provided with an arcuate slotll, Aand a `connecting rod 5, the latter being connecte-d to the Vlink 3by means of a pin 6 passing through the slot 4. The link 3 is'oscillated `about a point lying midway between the ends of the slot 6and hence the point of cut-olf is determined by the position of the pin6 in the slot il. This position may be varied by the engineer throughthe operation of the `reverse gear. In the ydrawings I have indi-cated apower-reverse gear 'l controlled from the cab by means of a rod 8.Extending Afrom 'the power-reverse mechanism is a .reach rod 9 pivotallyconnected to one arm of Aa bell-crank lever lfixed upon the tumblingshaft l i. The other arm of vthe bellcrank lever is connected by meansof a link I2 to the Ycut-orf valve connecting rod 5. Thus as the reversegear oscillates the ,bell-crank klever' I0 the position of the pin 6 ismoved up or down along the slot 4. The foregoing is standardconstruction and, of itself, forms no part of the prescnt invention.

Mounted within the cab of the locomotive is an instrument I3 providedwith a dial marked in miles per hour and having two coaxially mountedneedles or pointers. One of these Vindicates speed and is actuated Vbyany suitable means, preferl ably through connections with a frictionwheel I4, which engages the tread of one of the drivers.

The speed indicator driving mechanism illustrated is that described andclaimed in my co-pending applica-tion, ySerial No. 421,762, filedDecember 5,

1941, but any other driving mechanism such, for example, as the oneillustrated in the Caracristi Patent No. 1,704,381, might be employed.The second needle indicates cut-off and is responsive to changes incut-oi effected by the mechanism previously described. I shall nowdescribe the mechanism for actuating the cut-olf needle.

A cam I5, so designed as to convert cut-off factors into a singleexpression, is mounted within the instrument housing. A cam follower I6,which rises and falls With the oscillation of the cam, is mounted on arack I 'I which meshes with a pinion I8 xed with relation to the cut-ofIneedle I9, and thus the needle is swung as the cam is oscillated. Arecording mechanism may also be operated through the cam, asillustrated. The cam I5 is oscillated in response to oscillations of thetumbling shaft by means of the following mechanism: Fixed to thetumbling shaft I I is an arm 2I connected by means of a horizontal rod22 to a vertical arm 23 pivoted on the frame of the locomotive. The arm23 thus oscillates with the tumbling shaft. Between the arm 23 and thecam I5 I have interposed a hydraulic pressure transmitting system whichI shall now describe.

This system comprises a primary or driving cylinder 24 and a secondaryor operating cylinder 25 interconnected by means of tubing 25 and thewhole system filled with an oil or other suitable liquid. Each cylinderis provided with a piston and piston rod-27 and 28 respectively in thedriving cylinder, and 29 and 3U in the operating cylindereach piston rodextending on both sides of its piston and through stuing boxes in thecylinder heads. By this construction the volume of liquid displaced isequalized and the pistons are supported throughout the length of theirstrokes. The non-working end of each piston rod is provided with aprotective housing 3|. The piston rod 28 is connected to a cross-head 32sliding in ways 33. A connecting rod 34 extends from the cross-head 32to the lower part of the vertical arm 23 so that oscillation of thetumbling shaft causes reciprocation of the cross-head and of the piston2l. The piston rod of the operating cylinder 25 is provided at its upperend with a rack 35 which meshes with a pinion 36 xed to the cam I5.

As the engineer varies the cut-off by operation of the power-reversegear, the tumbling shaft is oscillated and with it the arm 2I, which,acting through rod 22, arm 23, connecting rod 34, cross-head 32, pistonrod 23 and piston 21 causes movement of the liquid in the two cylinders24 and 25 and the connecting tubing 26 of the hydraulic pressure system,which, in turn, acting through piston 29, piston rod 33, rack 35 andpinion 35, oscillates the cam l5, which in its turn actuates the cut-01Tneedle I9. Thus as the speed of the locomotive varies, the engineer cancorrespondingly vary his point of cut-01T to maintain the speedindicating and cut-off indicating needles in registry. Each branch ofthe tubing 25 is provided with a pressure equalizer 37 by means of whichthe setting of the cam I5 may be adjusted from time to time.

In order to adjust the throw of the connecting rod 34 to obtain correctpiston displacement for any tumbling shaft movement, I have provided theupper end of the arm 23 with a slot 38 for receiving the end of the rod22. The position of the end of this rod relative to the rod 34 may bevaried by means of two setscrews 39 bearing on opposite sides of abushing 40 in which a pin 4I on the end of the rod 22 is journaled.

The objects of my invention are attained by means of the apparatusillustrated and described. The cam has been moved to the instrumentitself Where it acts directly on the indicating mechanism without theinterposition of a long cable, thus increasing accuracy. The heavy cambox with its massive springs have been eliminated and the power requiredreduced. Expansion and contraction of the boiler do not introduce errorsof adjustment calling for continuous correction. In all of theserespects the present apparatus is an improvement over its predecessors.

It is common practice to combine recording with indicating mechanisms,and the term cutoi indicator used herein is intended to embrace either,or both.

I claim:

l. In a steam locomotive having means for varying cut-oit, a cut-01Tindicator in the cab of the locomotive, means at the indicator forconverting into a single expression factors governing cut-ofi whichproduce the maximum results at different speeds, means for actuating theindicator by the converting means, and means for actuating theconverting means in response to variations in cut-off.

2. In a steam locomotive having means for varying cut-off, a cut-offindicator in the cab of the locomotive, a cam at the indicator forconverting into a single expression factors governing cut-oli whichproduce the maximum results at different speeds, means for actuating theindicator in direct response to oscillations of the cam, and means foroscillating the cam in response to variations in cut-off.

3. In a steam locomotive having means for varying cut-off, a cut-offindicator in the cab of the locomotive, means at the indicator forconverting into a single expression factors governing cut-off whichproduce the maximum results at diierent speeds, means for actuating theindicator by the converting means, and a hydraulic pressure transmittingsystem for actuating the converting means in response to variations incutoff.

4. In a steam locomotive having a reverse gear, which varies cut-oli, acut-off indicator in the cab of the locomotive, a cam at the indicatorfor converting into a single expression factors governing cut-oli whichproduce the maximum results at dierent speeds, means for actuating theindicator in response to oscillations of the cam, and a hydraulicpressure transmitting system connected to both the reverse gear and thecam for oscillating the cam in response to variations in cut-off.

5. In a steam locomotive having a reverse gear, which varies cut-oit andincludes a tumbling shaft, a cut-od indicator in the cab of thelocomotive, a cam at the indicator for converting into a singleexpression factors governing cut-off which produce the maximum resultsat different speeds, means for actuating the indicator in response tooscillations of the cam and a hydraulic pressure transmitting systemextending between the cam and the tumbling shaft for actuating the Camin response to variations in cut-off.

6. In a steam locomotive having a rev-erse gear, which varies cut-01Tand includes a tumbling shaft, a cut-off indicator in the cab of thelocomotive, a cam at the indicator for converting into a singleexpression factors governing cut-oli which produce the maximum resultsat different speeds, a driving hydraulic cylinder adjacent the tumblingshaft, a piston in the cylinder, connections betW-een the tumbling shaftand the driving piston, an operating hydraulic cylinder adjacent theindicator, a piston in the cylinder, connections between the operatingpiston and the cam, tubing connecting the two cylinders, liquid nllingthe tubing and cylinders, whereby movement of the driving piston as thetumbling shaft is oscillated to vary cut-olf 'is transmitted to theoperating piston to actuate the cam in response to variations incut-off, and means for actuating the indicator in response tooscillations of the cam.

'7. In a steam locomotive having a reverse gear, which varies cut-oi'and includes ya tumbling shaft, a cut-off indicator in the cab of thelocomotive, a cam at the indicator for converting into a singleexpression factors governing cut-off which produce the maximum resultsat different speeds, means for actuating the indicator in response tooscillations of the cam, a hydraulic pressure transmitting systemextending between the cam and the tumbling shaft for actuating the camin response to variations in cut-off, and

means in the hydraulic pressure transmitting system for adjusting thecam.

8. In a steam locomotive having a reverse gear, which varies cut-off andincludes a tumbling shaft, a cut-olf indicator in the cab of thelocomotive, a cam at the indicator for converting into a singleexpression factors governing cut-off which produce the maximum resultsat diierent speeds, a driving hydraulic cylinder adjacent the tumblingshaft, a piston in the cylinder, connections between the tumbling shaftand the driving piston, an operating hydraulic cylinder adjacent theindicator, a piston in the cylinder, connections between the operatingpiston and the cam, tubing connecting the two cylinders, liquid fillingthe tubing and cylinders, whereby movement of the driving piston as thetumbling shaft is oscillated to vary cut-off is transmitted to theoperating piston to actuate the cam in response to variations incut-off, pressure equalizers in the tubing for adjusting the cam, andmeans for actuating the indicator in response to oscillations of thecam.

FAY D. WEIDEN.

